Researchers from Aalto University's Department of Applied Physics have reached a groundbreaking achievement by successfully connecting a time crystal to an external system for the first time. This innovative study, spearheaded by Academy Research Fellow Jere Mäkinen, details how the team transformed a time crystal into an optomechanical system, paving the way for advancements in technologies like ultra-precise sensors and enhanced memory systems for quantum computers.
The research findings were published in Nature Communications.
Mäkinen explains, "Perpetual motion is feasible within the quantum realm, provided it remains undisturbed by external energy inputs, such as observation. This is why a time crystal had never been linked to any external system before. However, we achieved this connection and demonstrated, for the first time, that the crystal's properties can be adjusted through this method."
Constructing and Maintaining a Time Crystal
To create this system, the researchers utilized radio waves to introduce magnons into a Helium-3 superfluid cooled to near absolute zero temperatures. Magnons are quasiparticles that behave collectively like individual particles. Once the radio wave input ceased, the magnons self-organized into a time crystal.
This time crystal maintained its motion for an extended duration, lasting up to 108 cycles or several minutes before its measurable effects diminished. As it gradually weakened, the time crystal interacted with a nearby mechanical oscillator, with the nature of this interaction varying based on the oscillator's frequency and amplitude.
Integrating Time Crystals with Optomechanics
Mäkinen further notes, "We demonstrated that variations in the time crystal's frequency are entirely analogous to optomechanical phenomena well-established in physics. These phenomena are utilized, for instance, in detecting gravitational waves at the Laser Interferometer Gravitational-Wave Observatory in the U.S. By minimizing energy loss and enhancing the frequency of the mechanical oscillator, our setup could be optimized to approach the quantum realm."
This connection to optomechanics is crucial as it enables control over the behavior of time crystals, a feat previously unattainable.
Implications for Quantum Computing and Sensing
Time crystals hold significant potential for the advancement of quantum technologies due to their remarkable longevity compared to conventional quantum systems. Mäkinen states, "Time crystals can persist for orders of magnitude longer than current quantum systems used in computing. In an ideal scenario, they could revolutionize quantum computer memory systems and serve as frequency references in high-sensitivity measurement devices."
This research was conducted at the Low Temperature Laboratory, part of OtaNano, Finland's national infrastructure for nano-, micro-, and quantum technologies, with computational resources provided by the Aalto Science-IT project.